XBoard invokes an external sound-player program to produce sounds. In
the Options -> Sounds dialog it can be selected which one. So the first
step would be to look there to see what sound-player XBoard is
configured to use. Then you can check if that sound-player command works
from the command
I have installed XBoard 4.8.0.20151020 on my operational system GhostBSD
11.1-amd64, all is OK, the program plays, analyses etc., but I do not
hear any sound. There are NVIDIA driver ver.390.77 and Realtec AC-97
built-in sound driver on my machine. PLayers work, so as WEB browser, I
can listen